NEW YORK--(BUSINESS WIRE)--New York Life announced today that Senior Vice President Mark Madgett will succeed Executive Vice President Mark Pfaff as head of the Agency Department, which manages the company’s field force of 12,000 career agents in cities and towns across the country. Mr. Pfaff, 57, plans to retire from the company at year-end 2015 following 30 years of distinguished service as an agent, field manager and Home Office executive. Mr. Madgett, 54, joined New York Life as an agent in